The present invention relates generally to methods of operating mineral comminution machinery to obtain optimum performance, and specifically relates to such a method of operating a crusher such as a jaw crusher.
Conventional mineral crushers such as jaw crushers or conical crushers share operating parameters and performance characteristics such as stroke or head throw, eccentric speed, horsepower draw, throughput capacity and crushing force. Crusher stroke may be defined as the displacement of the head or jaw between widest and narrowest points on an eccentrically gyrating cycle. Eccentric speed is self explanatory, while horsepower draw is the amount of power consumed, and is a function of stroke, crushing force and eccentric speed. Throughput capacity is described in terms of tons per hour, and crushing force is generally represented by dividing horsepower by the product of stroke and eccentric speed.
A longstanding problem in the operation of such machines is the adjustment of the above-identified parameters so that capacity is maximized while the crushing force is maintained below a machine-specific maximum design level. More particularly, in regard to jaw crushers, the object is to increase capacity by increasing horsepower draw without increasing normal crushing force. If the crushing force is increased, the crusher frame will necesarily need to be strengthened in order to withstand the higher crushing loads normally associated with increased horsepower. However, conventional crushing theory dictates that if horsepower is increased, so will the crushing force.
Thus, an object of the present invention is to provide a method of adjusting a jaw crusher in order to increase capacity without increasing crushing force.
Another object of the present invention is to provide a method of adjusting a jaw crusher in which an optimum combination of horsepower, stroke and speed will be established to obtain optimum throughput capacity.